1. Field of the Invention
This invention relates to chemical dispensers, and more particularly, pertains to improvements in automated pool treatment systems.
2. Description of the Prior Art
Chlorine and other chemicals are used in swimming pools and spas to control growth of algae and other organisms therein Additional chemicals are used to regulate the water's pH. The chlorine concentration must be maintained in a range below the level harmful to pool users, and above the minimum level effective to eliminate the undesired organic growth. Similarly, only a relatively narrow range of pH can be comfortably tolerated by the pool users. A number of different factors all contribute to the continual decline of the critical chemical concentration levels and periodical replenishment is therefore necessary.
Heretofore disclosed systems have provided semi-automated and fully automated systems to achieve this function. Aside from the problems associated with dispensing the proper amount of chemical at the appropriate time, many complications arise in trying to provide a system capable of functioning in a reliable, trouble-free manner for extended periods of time. The dispensation of chemicals in solid form into water, especially water at elevated temperatures, often results in encrustment, blockage and ultimate failure of the equipment.
For example, a particular situation often encountered in the chlorination of pools and spas involves the dispensation of sodium dichlor in its dry powdered or granulated form. Sodium dichlor contains about 56% active chlorine plus cyanuric stabilizer and is a desired vehicle for introducing chlorine into the water because of its almost neutral pH (6.5) and high solubility. Its extremely hydrophilic nature, however, tends to attract and absorb water which causes it to become extremely sticky. The moisture-laden chemical has the tendency to adhere to various surfaces and over time forms a thicker and thicker crust thereon which can ultimately debilitate or block various mechanisms and functions associated with such surfaces. A condition compounding the encrustment problem in spa systems is inherent in the fact that the water is heated substantially above ambient. Under such conditions it is more likely that condensate forms on the various components, and consequently, the chemical is more likely to be attracted and adhere thereto. The prior art has not adequately addressed this problem and an improved system is called for that is not susceptible to encrustment or clogging.
A number of different methods have been employed to control the rate of chemical dispensation in such automated devices. Typically a batch process is used whereby a preset amount of chemical is dispensed with each dispensation cycle while the cycling rate is controlled either by a timer or other control means. It may be desirable to alter or fine tune the amount of chemical dispensed during each cycle and it is here that a similar improvement over the prior art is called for wherein the amount dispensed is quickly and easily alterable by a mechanism that is not susceptible to encrustment or blockage.
Sensors that monitor chlorine content or pH are often employed to control the dispensation of the appropriate chemical. It is most desirable to integrate such a sensor within the chemical dispensation system itself in such a manner so as to provide accurate results and avoid the complexity associated with the fitment of a sensor to existing pool or spa hardware.